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The web of human sexual contacts

Promiscuous individuals are the vulnerable nodes to target in safe-sex campaigns.

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Figure 1: It's a small world: social networks have small average path lengths between connections and show a large degree of clustering.
Figure 2: Scale-free distribution of the number of sexual partners for females and males.


  1. 1

    Strogatz, S. H. Nature 410, 268–276 (2001).

    ADS  CAS  Article  Google Scholar 

  2. 2

    Kochen, M. (ed.) The Small World (Ablex, Norwood, New Jersey, 1989).

    Google Scholar 

  3. 3

    Wasserman, S. & Faust, K. Social Network Analysis (Cambridge Univ. Press, Cambridge, 1994).

    Google Scholar 

  4. 4

    Lewin, B. (ed.) Sex i Sverige. Om Sexuallivet i Sverige 1996 [Sex in Sweden. On the Sexual Life in Sweden 1996] (Natl Inst. Pub. Health, Stockholm, 1998).

    Google Scholar 

  5. 5

    Milgram, S. Psychol. Today 2, 60–67 (1967).

    Google Scholar 

  6. 6

    Watts, D. J. & Strogatz, S. H. Nature 393, 440–442 (1998).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Barthelemy, M. & Amaral, L. A. N. Phys. Rev. Lett. 82, 3180–3183 (1999).

    ADS  CAS  Article  Google Scholar 

  8. 8

    Amaral, L. A. N., Scala, A., Barthélémy, M. & Stanley, H. E. Proc. Natl Acad. Sci. USA 97, 11149–11152 (2000).

    ADS  CAS  Article  Google Scholar 

  9. 9

    Simon, H. A. Biometrika 42, 425–440 (1955).

    MathSciNet  Article  Google Scholar 

  10. 10

    Barabási, A.-L & Albert, R. Science 286, 509–512 (1999).

    ADS  MathSciNet  Article  Google Scholar 

  11. 11

    Laumann, E. O., Gagnon, J. H., Michael, R. T. & Michaels, S. The Social Organization of Sexuality (Univ. Chicago Press, Chicago, 1994).

    Google Scholar 

  12. 12

    Hethcote, H. W. & Yorke, J. A. Gonorrhea Transmission Dynamics and Control (Springer, Berlin, 1984).

    Google Scholar 

  13. 13

    Pastor-Satorras, R. & Vespignani, A. Phys. Rev. Lett. 86, 3200–3203 (2001).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Albert, R., Jeong, H. & Barabási, A.-L Nature 406, 378–382 (2000).

    ADS  CAS  Article  Google Scholar 

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Correspondence to Fredrik Liljeros.

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Liljeros, F., Edling, C., Amaral, L. et al. The web of human sexual contacts. Nature 411, 907–908 (2001).

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